Vernier tuning mechanism



Feb. 6, 1934.

D. P. EARNSHAW VERNIER TUNING MECHANISM Filed Sept. 23, 1930 "NHNI PI INHI IH Patented Feb. 6, 1934 PATENT? OFFICE VERNIER TUNING MECHANISM David 1. Earnshaw, Philadelphia, Pa., assignor to Philadelphia Storage Battery Company, Philadelphia, Pa., a corporation of Pennsylvania Application September 23, 1930 Serial No. 483,897

10 Claim.

An object of the invention is to provide anaccurate and efllcient position adjustment mechanism of simple construction.

Another object is to provide a tuning mecham nism for a radio receiver which will permit such fine adjustment of the condensers that any one of several stations having relatively closebroadcast frequencies may be tuned in to the exclusion of the others in a minimum. of time and with little efiort on the part of the operator.

A further object is to provide such a mechanism as will permit a finer adjustment of the condensers than has heretofore been practical with 20 simple prior art mechanisms.

' A still further object is to provide a mechanism of novel structure coarse and fine adjusting means.

A still further and more specific object of my invention is to provide a tuning mechanism for radio receivers having a Vernier for fine tuning and wherein the vernier disk may be used to spin or "crank the indicating dial to an approximate or coarse adjustment position.

39 These and other objects and ends are obtained by means of the mechanism illustrated on the actuning having both companying drawing, to which reference will behad in connection with the following detailed description, and. in which Fig. 1 shows a plan view of a portion of the front panel of a radio receiver having associated therewith my improved position-adjusting device and the associated variable condensers of a radio receiver; and Fig. 2 is a front yiew of the panel portion shown ivrii Fig. 1 and the associated elements of my dece. Referring to Fig. 1 a portion of a condenser shaft 1 is shown having mounted thereon the rotors 2 of the variable tuning condensers of a radio receiver. A graduated dial 3 to indicate the position of the shaft, and a gear 4 are also mounted on the shaft 1. Geared to shaft 1 by means of a worm meshing with gear 4 is a drive shaft 5. The ratio between the gear teeth and worm may be 40 to 1, so that forty revolutions of shaft 5 are necessary to cause shaft 1 to makev one revolution. Keyed to shaft 5 so as to rotate therewith is a graduated dial 6. A housing 7 is also 55 mounted on shaft 5, but is not keyed thereto and is, therefore, rotatable on shaft 5. This housing encloses dial 6, as shown. Shaft 5 protrudes through panel 8, a portion only of which is shown. Shaft 5 may, of course. be supported in suitable bearings (not shown). If desired, the 66 opening in panel 8, through which shaft 5 extends, could be provided with a bushing to act as" one bearing support for the shaft. Or, if the panel is of metal or the like, a bushing might be unnecessary, the panel itself serving as a bear-- a ing support.

As shown more clearly in Fig. 2, housing 7 is provided on its side .edge with a recess 13. An. angle member 9 having a pointed portion 12, which is adapted to protrude into recess 13, is pivotally mounted at 10 adjacent housing 7. The mounting for member 9 may comprise a bolt or pin 11 which extends through and' is fastened to panel 8 in any desired manner, such as by means of a pair of nuts threadedly' engaging w bolt 11 on each side of the panel. A knob or finger rest 14 is attached to or formed integral with pin 15 which passes through a hole in the end of member 9. A spring 26 urges member 9 in a clockwise direction around pivot 10 so that portion 12 w may engage recess 13. An angular supporting member 16 for spring 15 is attached to panel 8. in any suitable manner, such as by means of a threaded bolt 17 extending through the panel and fastened thereto by a nut on the inside thereof. Pin 15 also passes through a hole in the horizontal portion of member 16, and is provided at its lower extremity with an integral or attached 1 head or nut. A shoulder of knob 14 engages the upper surface of member 9 so that when the knob W is pressed, it rotates member 9 in a counter clockwise direction against the action of the spring, pin 15 moving downward through the hole in member 16. v

Mounted rotatably on one end of a spindle 18 i on housing 7 is a Vernier disk 19 which is adapted to frictionally engage dial 6, as is well known in the art. The ratio of the bearing circumferences of dial 6 and disk 19 may be 10 to 1, so that it' takes ten revolutions of disk 19 to revolve dial 6 once. A knob 20 is provided on the other end of spindle 18, whereby disk 19 may be manually turned. 'A window 21 with a hair 1ine25 is provided in panel 8, so that the position of dial 3 can be accurately read. However. any other suitable arrangement for determining accurately the position of the dial may be used. A window 22 anda hair line 23 are provided on housing 7 so that the position of dial 6 may be read. Obviously. any

other arrangement for facilitating adjustment of the Vernier dial may be used. A cap 24 is provided on the end of shaft 5.

The dial 3 is preferably provided with twenty equally spaced lines or calibrations over 180 of its circumference, while dial 6 is provided with two hundred equally spaced lines over its entire periphery. These dial calibrations may, of course, take the usual form of a group of major lines equally spaced with groups of eqully spaced minor lines therebetween. For example, every fifth line on dial 3 may be a major line and may have a marking in kilocycles or meters adjacent thereto on the dial. Likewise, every fifth line on dial 6 may be a major line'and may be numbered 5,10, etc. up to 200. Any other method of marking the dials may, of course, be used.

To obtain a coarse adjustment of the condensers, it is only necessary to press the knob 14 to actuate the locking device against the action of its spring to unlock housing 7, place the fingers on Vernier knob 20, and crank the housing 7 the desired number of revolutions, thus cranking the shaft 5 to a desired position. The frictional engagement of disk 19 and dial 6 will, of course, cause the dial and shaft to revolve. After a coarse setting, as indicated on dial 3, has been obtained, a fine adjustment may be obtained by releasing the locking device to lock housing 7 at one definite point and by turning the vernier knob 20 to adjust the Vernier dial. It will be obvious that one turn of shaft 5 is necessary to advance dial 8 one division and that a setting of one twohundredth of a division on dial 3 can be obtained by means of the vernier, there being four thousand obtainable divisions of dial 3.

While I have indicated above the number of dial divisions and the movement ratios of respeotive elements which I have found desirable, it will be apparent that these may be varied to give any degree of fine tuning. The size of the various elements may, of course, be varied, and the degree of fine adjustment obtainable with my device is limited only by the practical limitation which must be placed on the dimensions of the elements.

It will be seen that I have provided a novel and extremely precise tuning mechanism. My

' invention is, of course, capable of various modificatlons, which will be apparent to those skilled in the art, and it is to be understood that the specific embodiment disclosed herein is for the purpose of illustration only. My invention is, therefore, to be limited only by the-prior art as reflected in the scope of the appended claims.

I claim: a

l. A mechanism for adjusting the position 01' a rotatable member, comprising crank means arranged for successive rotation to effect different positions of said member for difierent revolutions, whereby a coarse position adjustment of said member may be obtained, vernier means for obtaining a fine position adjustment of said member, and indicating means for each of said adjusting means.

2. In a device for adjusting the position of a rotatable member, having position-indicating means mounted thereon and a driving member geared thereto, a dial fixedly mounted on said driving member, a housing rotatably mounted on said driving member, and a friction device between said dial and said housing and having an operating knobwhereby manual rotation of said housing while the knob is manually grasped will impart motion to said rotatable member.

3. In a device for adjusting the position of a rotatable member, having position-indication means mounted thereon and a driving member geared thereto, a dial-fixedly mounted on said driving member, a housing rotatably mounted on said driving member, a Vernier disk rotatably mounted on said housing and adapted to frictionally engage said dial, and a knob on said housing for rotating said disk, whereby said rotatable member -may be rotated rapidly by utilizing said knob to turn said housing while said disk engages said dial and said rotatable member may also be rotated less rapidly by turning said knob while holding said housing stationary.

4. In a device for adjusting the position of a rotatablev member, having position-indicating means mounted thereon and a driving member geared thereto, a graduated dial fixedly mounted on said driving member, a housing of greater diameter than said dial rotatably mounted on said driving member, a Vernier disk rotatably mounted on said housing and adapted to frictionally engage said dial, a knob on said housing for rotating said disk, and means for locking said housing against rotation, whereby said rotatable member may be rotated rapidly by utilizing said knob to turn said disk while the locking means is ineifective and said rotatable member may also be rotated less rapidlly by turning said knob while the locking means is effective.

5. In a device for adjusting the position of a rotatable member, having position-indicating means mounted thereon and a driving member geared thereto, a graduated dial fixedly mounted on said driving member, a housing of greater diameter than said dial rotatably mounted on said driving member, a rotatable disk having an operating knob on said housing adapted to frictionally engage said dial and to constitute therewith vernier adjusting means for said rotatable member while said housing is held stationary and to constitute therewith crank adjusting means for said rotatable member while said disk is movable, and spring biased locking means for said housing.

' 6. In a radio tuning mechanism for adjusting the position. of shaft-mounted condensers, a graduated dial on said shaft for indicating coarse adjustments, a drive shaft geared to said condenser shaft, a graduated dial on said drive shaft for indicating fine adjustments, a housing rotatably mounted on said drive shaft, a disk rotatably mounted on said housing and adapted to frictionally engage said dial, a knob on said housing for rotating said disk, and locking means for said housing, whereby a. coarse adjustment of the conv densers may be obtained by utilizing said knob to turn said housing while said disk engages said dial and said locking means is inefiective, and a fine adjustment of said condensers may be obtained by turning said knob while said locking means is effective.

'7. In a device for adjusting the position of a rotatable member, having position-indicating means mounted thereon and a driving member geared thereto, position-indicating means carried by said driving member, crank means for rotating said driving member to obtain a coarse position adjustment of said rotatable member as indicated by said first indicating means, and vernier means for rotating said driving member to obtain a fine position adjustment of said rotatable member as indicated by said second indicating means.

8. In a device for adjusting the position of a rotatable member, having position-indicating means moimted thereon and a driving member geared thereto, position-indicating means carried by said driving member, crankmeans Ior rotating said driving member to obtain'a coarse position adjustment of said rotatable member as indicated by said first indicating means, and vernier means associated with said crank means for rotating said driving member to obtain a flne position adjustment of said rotatable member as indicated by said second indicating means.

- 9. In a device for adjusting the position of a rotatable member, having position-indicating means mounted thereon and a driving member geared thereto, a dial fixedly mounted on said driving member, a member rotatably mounted on said driving member, a driving connection between said dial and said last-named member and having an operating knob, said connection being adapted to move said dial with said last-named member or independently thereof, and means for locking said last-named member against rotation, whereby said rotatable member may be rotated rapidly by utilizing said knob to turn said last-named member while the locking means is 'inefiective, and said rotatable member may also be rotated less rapidly by turning said knob while the locking means is efiective.

10. In a device for adjusting the position of a rotatable shaft, a dial fixedly mounted on said shaft, a member rotatably mounted on said shaft,

a driving connection between said dial and said 

